Spiral broach device



May 16, 1939. w. A. HART- SPIRAL BROACH DEVICE Filed .July 19, 1935 3 Sheets-Sheet l INVENTOR. M'JZJ'd/f f2 Har?. B'r

ATTORNEYS.

v M115 16, 1939 w. A. HART sPrRAL BRoAcH DEVICE Filed July 19', 1935 3 Sheets-Sheet 2 Z a @al z 3f, w

JMW L@ 0 ATTORNEYS,

May 16, 1939.V w A. HAR-r 2,158,720

SPIRAL BROAGH DEVICE 4 Filed July 19, 1935 3 Sheets-Sheet 3 A TTORNEYS.

Patented May 16, 1939 PATENT OFFICE SPIRAL BBOACH DEVICE William A. Hart, Detroit, Mich., assirnor to Colonial Broach Company, a corporation of Michigan Application July 19, 1935, Serial No. 32,230

6 Claims.

The present invention relates generally to machines for operating metal working tools, and more particularly to automatic broaching machines arranged to produce a spiral cutting action.

It is an object of the present invention to provide a broaching machine constructed to cut spiral grooves in circular or other stock.

It is a further object of the present invention to provide a breaching machine of the above type which is conveniently adjustable to produce either a spiral or a straight broachlng action..

It is a further object of the present invention to provide a broaching machine embodying mechanism to draw a broach past stock and. to

i5 simultaneously impart a rotative movement to the broach.

It is a further object of the present invention to provide a broaching machine of the last mentioned type and embodying means to cause the rotative motion of the breaching tool to occur in a definite timed relation to the drawing movement of the broach.

It is a further object of the present invention to provide a breaching machine embodying pullbar mechanism disposed to draw a breaching tool past a Work piece and a rotative head disposed to impart rotative movement to the broach.

It is a further object of the present invention to provide a broaching machine of the last mentioned type in which the second or rotative mechanism is actuated by and in accordance with the movement of the iirst element.

It is a further object of the present invention to provide a broaching machine of the last mentioned type in which the rotative mechanism 1s supported for movement'along a spirally cut lead screw in accordance with the movement of the pull bar mechanism, and is thereby rotated to effect a corresponding rotation of the broaching tool.

It is a further object of the present inventlon to provide a broachng machine as above mentioned and embodying means to readily disconnect the tool head from the rotation mechanism.

It is a further object of the present invention to provide a broaching machine having a 'rotatable head, driven along a spiral lead screw by a pullbar to thereby rotate a broaching tool, and embodying indexing mechanism to conveniently adjust the relative angular positions of the lead screw and broaching tool.

It is a further object of the present invention to generally improve and simplify the construction and operation of spiral broaching tools, and

to produce a tool which is economical oi manufacture and accurate and positive in operation.

Other objects and advantages of the present invention appear in the following description and in the appended claims.

ln the drawings, throughout which corresponding reference characters are used to designate corresponding parts,

Figure 1 is a view in perspective of a spiral biroach machine embodying the present invent on;

Fig. 2 is a view in vertical section of a broaching tool head embodying the present invention;

Fig. 3 is a view in vertical end section taken along the lines 3-3 of Fig. 2;

Fig. 4 is a view in end elevation, partly in section, taken along the line 4 4 of Fig. 2;

Fig. 5 is a fragmentary view in vertical section of a modiiied embodiment of the present invention;

Fig. 6 is a view in end elevation, partly in section, of the embodiment shown in Fig. 5, and

Fig. 'l is a fragmentary sectional view of a portion of the indexing mechanism shown in Figs. 5 and 6, and taken along the line 'I-l of Fig. 6.

In the form illustrated, the broaching machine of the present invention, comprises generally a stationary table disposed to support a Work piece in cooperative relation to a broaching tool; a tool head having driving and driven rotatable elements, the driven element being connected to a breaching tool, and the driving element being operatively connected to a spiral lead screw; and a pull bar disposed for movement in a rectilinear reciprocatory path and connected to the tool head, so that rectilinear movement of the pull bar effects a corresponding rectilinear movement of the tool head and breach, and elects a rotative movement of the driving element of the tool head to thereby correspondingly rotate the broaching tool in timed relation to the rectilinear movement thereof.

The pullbar may be actuated in various ways, a fluid pressure operated cylinder being shown in the drawings by Way of illustration. Similarly, the work piece may be supported on the machine table in various ways, a simple, vertical support being shown in the drawings, adapted to stationarily secure the work piece in position to permit a tool to be drawn through an opening therein. The tool head may comprise generally a housing, directly connected to the pullbar, and within which a rotatable driving element and a rotatable driven element are suitably supported and geared together. The driving element is formed to cooperate with a spirally cut lead screw which is stationarily supported on the machine table in spaced parallel relation to the path of the pullbar. With this arrangement, as will be understood, rectilinear movement of the pullbar, causes the driving element to be rotated by the spirally cut lead screw at a rate determined by the rate of rectilinear movement and by the lead of the spiral.

The driven element, also rotatably supported within the head, as above mentioned, is illustratdas directly geared to the driving element and accordingly is rotated at a rate proportional to the rate of rotation of thedriving element. The broaching tool is directly connected to the driven element by an improved form of connection described in more detail hereinafter and rotates directly therewith. The broaching tool is formed with spirally cut teeth, preferably as described and claimed in the patent to Carl J. Halborg, No.V 2,011,630, of August 20, 1935, and Axel L. Nilsson, No. 2,060,889, of November 17, 1936, both assigned to the same assignee as the present application. It will be understood, therefore, that as the broaching tool is advanced through the work piece, moving both rectilinearly and rotatively, a spiral groove is cut in the work piece.

In further accordance with one illustrated embodiment of the present invention, the machine is readily convertible to provide either straight or spiral broaching. As illustrated, this conversion is effected by disconnecting the driving and driven elements of the tool head, thus eliminating the rotational movement of the broach. An improved arrangement is also provided to secure the broach in a predetermined rotative position upon disconnection from the driven element.

The present invention also provides for the broaching of a plurality of spirals using a broach having a single row of teeth, by indexing the rotative position of the broach with respect to the lead screw. In accordance with one embodiment, the indexing may conveniently be accomplished by releasing the lead screw and rotating it through a predetermined angle. In accordance with a modified embodiment of the present invention. the indexing is accomplished by disengaging the driving and driven elements of the tool head, and rotating the driven element through a predetermined angle with reference to the driving element.

Considering the above mentioned elements in more detail, and referring first to the perspective view of Fig. l, the machine I8 is of the horizontal type, and embodies the somewhat elongated channel I2, within which the broaching tool I4, the tool head designated generally I6, and the pullbar I8 are supported. Pullbar I8 is suitably connected for actuation by fluid pressure actuated mechanism comprising the cylinder 20. The machine table also comprises a vertical standard 26, disposed at an intermediate point in channel I2, and against the rear surface 28 of which illustrative work piece 36 is seated.

One end of broaching tool I4 is supported in a clamp 3l, which is slidable along a trackway formed on the interior of channel I2. The other end of broaching tool I4 is connected to the driven element of tool head I6, later described. The driven element of tool head I6, later described, is connected to lead screw 32, the opposite ends of which are secured in bosses 33 and 34, which are suitably secured to the machine table. A locking member 36 associated with lead screw 32 is provided to release it so that it may be rotated to" effect an indexing action, as later described.

Illustrative control mechanism for cylinder 20 comprises motor 22 which may be connected by belting 24 to a suitable pump (not shown) to supply fluid under pressure to cylinder 20. The starting and stopping may be controlled in any well known manner by the illustrative foot pedal 38. The control elements per se form no part of the present invention and have not been illustrated in detail.

Referring particularly to Figs. 2 and 3, pullbar I8 is rigidly connected to the forwardly extending boss portion 40 of tool head I6. As best shown in Fig. 3, opposite sides of boss 40 are provided with guide grooves 42 which cooperate with rail portions 44 extending inwardly from the sides of channel I2, and which support and guide the movements of the tool head assembly within channel I2. The housing of tool head I6 is formed in two separable portions 46 and 48, which are secured together by studs 50.

The driving element of tool head I6 comprises the gear 52, rotatably supported within the upper portion of members 46 and 48 on the roller bearing assembly 54. Gear 52 is removably but nonrotatably secured to a driving sleeve 56 by key 58, which enters a key-Way 60 formed within gear 52 and a corresponding key-way 62 formed on the exterior of sleeve 56. Gear 52 is centered within the housing portions 46 and 48 by the ball bearing assemblies 54 and sleeve 56 is centered with respect to gear 52 by the lock nuts 64, which are threadably secured at one end thereof.

The respective ends of driving sleeve 56 are apertured, and are provided with inwardly extending teeth portions, such as portion 66, which enter grooves 68 cut in the surface of lead screw 32. As best shown in Fig. 3, lead screw 32 is provided with three equi-distantly spaced spiral grooves 68, and it will be understood, therefore, that driving sleeve 56 is provided with a corresponding number of inwardly extending teeth 66. The teeth 66 and grooves 68 form a driving connection between lead screw 32 and gear 52, and it will be understood that rectilinear movement of tool head I6 along lead screw 32, as actuated by pullbar I8 and the associated mechanism, results in rotating gear 52 at a rate determined by the lead of the grooves 68 formed in screw 32.

The left hand end of lead screw 32 is secured by adjusting screw 36 within a bearing boss 34 which is rigidly secured to the previously mentioned upright standard 26 by one or more studs 14. screw 32 against rotation, but may be backed away to permit a rotative movement of the latter. It will be understood that any rotation of lead screw 32 correspondingly rotates the driving gear 52 and effects a change in the angular relationship between lead screw 32 and the driven portions of the tool head.

The driven element of tool head I6 comprises the gear 16, which meshes with gear 52 and the tool puller sleeve 18, the shank of which is suitably keyed to gear 16 by keys 8U, and which extends on one side thereof to provide an engaging portion for broaching tool I4, and extends on the other side thereof to threadedly receive the collar 82. rotatably supported within the lower parts of housing portions 46 and 48 on the pair of radial ball bearing units 84 and the thrust ball bearing unit 8 6. 'I'he packing gland 88 is preferably provided, to prevent the escape of lubricant from Adjusting screw 36 normally secures lead i Sleeve 'I8 and, consequently, gear 16 are n K 2,158,720 within the head I6. As will be understood, the

ball bearing units 84 and 86 serve to center gear 16 within the housing portions 46 and 48 and that the retaining collar 82 prevents axial movement between sleeve 18 and gear 16.

The puller sleeve 18 is bored out at 88 to receiv'e the end of broaching tool I4. As best shown in Fig. 4, a pin 92 passesthrough the side opening 94 in sleeve 18 and through a correspending opening 86 which passes transversely through the end of tool I4, and prevents rotative movement between sleeve 18 and tool I4, as well as limiting axial movement therebetween. Axial relative rotation of tool I4 and sleeve 18 is additionally prevented by the plate 98 which is secured to the face of sleeve 18 by studs |00 and the `lower edge of which partially closes off the opening 90 in sleeve 18. It will be understood that the upper edge of tool |4, as viewed in Fig. 4, is correspondingly cut away toaccommodate plate 88. Retaining ball I 02 is loosely received in an opening |04 formed in sleeve 18 and is biased inwardly to the position shown in Fig. 4 by a l spring |06 which seats against a plug |88 threaded into sleeve 18. Pin 92 is recessed at IIUto receive ball |02. Spring |86 is of sufiicient stress to retain ball |62 in recess 0 and overcome any tendency of pin 92 to fall out of sleeve 18 during rotation of the assembly but, as will be understood, is weak enough so that pin 92 may be readily withdrawn when desired, to permit the insertion of a broaching tool in puller sleeve 18.

With reference to the operation of the above described embodiment as a whole, it will be understood that the machine is prepared for operation by removing broaching tool I4v from sleeve 18 and slipping a work piece 30 over the puller end thereof. Thereafter, tool I4 is again inserted in sleeve 18 and pin 82 secured in place. Clamp 3| (Fig. 1) is then applied to the following end of tool I4 to maintain the latter in alignment. Work piece 30 is disposed adjacent the rear surface 28 of standard 26, as previously described. Upon actuation of the driving cylinder associated with pullbar I8, which, as above mentioned, may be effected in various well known ways in response to operation of control pedal 38, pullbar I8 and driving head I6 move to the right as viewed in Figs. 1 and 2, thereby drawing tool I4 through work piece 30.

The rectilinear motion of tool head I6 moves driving gear 52 along lead screw 32, causing the former to rotate at a rate determined by the lead of screw 32. Thisrotation is transmitted to gear 16 and hence to puller sleeve l18 and tool I4. Tool I4, therefore, rotates with respect to work piece at a rate bearing a denite relation to the rate of rectilinear motion thereof. As previously described, the cutting edges of tool I4 are spirally formed, having a lead corresponding to nthe above ratio between rotative and rectilinear movement. Accordingly, tool I4 cuts a spiral groove on the inner surface of work piece I3, having the same lead as the teeth on tool I4.

The driving mechanism of the present invention may also be used to cut a plurality of definitely spaced spiral grooves in a work piece, through action of a broaching tool having a single spiral of cutting teeth. As previously described, adjusting screw 36 may be backed 01T to withdraw the end thereof from engagement with Screw 32, and to permit rotation of screw 32 within its support. This rotation effects a corresponding rotation of gears 52 and 16 and, consequently, of tool I4. Accordingly, for a particular longitudinal position of the driving head I6 along its path, any desired angular position of broaching tool I4 is possible, and a single groove in work piece 30 may be cut corresponding to each of such angular positions.

It will be understood that the movement of pull bar I8 may be interrupted at the end of a cutting stroke, either automatically or manually in various well known ways. For example, it may be accomplished by the release of pedal k38. Similarly a re-setting movement thereof to the starting position may be accomplished in various ways, such as Vby reversing the connections to cylinder `20. The mechanism for accomplishing this reversing control forms no part of the present invention and has b'een omitted from the drawings to Vsimplify them.

The embodiment of the present invention shown in Figs. 5, 6 and 7 is adapted to provide Vin a predetermined, rotative position, and as described in more detail below the locking mechanism may be also used as an indexing arrangement to permit the driven element to be indexed to any one of a plurality of predetermined, angular, rotative positions.

Referring particularly to Figs. 5 and 6, driving head |20 is formed of two separable portions |22 and |24 respectively, which are disposed to be connected together by a plurality of studs |26, such as described in connection with the rst embodiment. Pullbar |28 is directly connected to the portion |24 and may be connected to actuating mechanism as described above. Similarly, lead screw |36, which is preferably formed as described in connection with lead screw 32, is suitably supported in stationary relation with respect to the machine by the bearing boss mechanism designated generally |32.

The driving gear |34 is slidably tted over a sleeve |4I, but is secured against rotation with respect thereto by the key |36 which enters a key-way formed in gear |34 and is secured by studs |44 in a key-way formed in sleeve |4|. Sleeve |4| is rigidly secured to the driving sleeve |42 by key |45. Driving sleeve |42 and the locking collars |46 associated therewith correspond in all respects to driving sleeve 56 and locking collar 64 described in connection with Fig. 2, and provide a driving connection between gear |34 and lead screw |30. Ball bearing units |48 are interposed between housing portions |22 and |24 and sleeve |4I, and the usual packing glands |50 are preferably provided to prevent the escape of lubricant between sleeve |4| and the housing.

Gear |34 is provided with an annular recess |52, within which the two spaced arms |54 of a conventional shifting fork |56 are received. The head of clutch |56 is received withina recess |58 in an actuating bar |60, which is slidably secured within a guide |63. Guide |63 is fixed to the housing by studs |65. The spring biased detent |62 cooperates with notches |64 and |66 in bar.

|68 to adjustably retain the latter in either a driving or a non-driving position. It will be understood that by forcing bar to the left as viewed in Fig. 5, detent |62 is withdrawn against the force of spring |68, and that gear |34 is moved to the left from the illustrated position, to a position in which it is` out of mesh with the driven gear |10.

The driven gear |10 is preferably associated with a puller sleeve |12'in the manner described in connection with Fig. 2, and these elements are rotatably mounted within the housing portions |22 and |24 on the radial ball bearing units |14 and the thrust ball bearing unit |16. It will be understood that puller sleeve |12 may be associated with a broaching tool in the manner described in connection with the first embodiment. It will also be understood that with the parts in the positions illustrated in Fig. 5, in which driving gear |34 is inE mesh with driven gear |10. that the operation of the machine corresponds in all respects to the operation of the first described embodiment. It is thought unnecessary, ttfpefore. to further describe such operation.

The mechanism for retaining puller sleeve |12 in a definite rotative position with respect to the driving head |20 comprises the detent |18 which is slidably disposed in a recess |80 bored out of the housing portion |24, and is urged outwardly therefrom by a compression spring y|82 which is seated between the end of detent |18 and the housing portion |24. The tapered end |84 of detent |18 is disposed to enter a cooperating recess |86 formed at the rear surface of the driven gear |10.

Trunnion |86, which is eccentrically formed with respect to the adjusting shaft |88, is disposed to enter a cooperating transverse recess |89 formed in detent |18. Shaft |88 is snugly but rotatably supported within the housing portion |24, and is provided at its upper and exterior end with an adjusting head |90. It will be understood that rotation of head |90 causes eccentric trunnion |86 to move in an arcuate path, and to slide within the transverse recess |89 formed in detent |18. The arcuate movement of trunnion |86 effects a longitudinal movement of detent |18, to the right or to the left as viewed in Figs. and 7, into and out of engagement with gear |10.

It will be understood that during the operation of the machine for spiral broaching, with the parts in the positions shown in Fig. 5, that head |90 is maintained in a position in which detent |18 is withdrawn from operative engagement with the driven gear |10, so that the latter rotates freely in response to the rotation of the driving gear |34. To convert the machine for straight broaching, the driven gear is brought to a position in which the recess |86 is opposite detent |18 and is locked in that position by rotating head |90 to move detent |18 into recess |86; and bar |60 is actuated to move gear |34 out of mesh with gear |10. The longitudinal movement of tool head is not accompanied by any rotative movement thereof, and a straight broaching action is effected.

In further accordance with the present invention the rear face of the driven gear |10 may be provided with a plurality of angularly spaced recesses corresponding to the recess |86 shown in Fig. 7, so that gear |10 and puller sleeve |12 may be locked in any one of a plurality of rotative positions with respect to the driving head 20. With this arrangement, it will be evident that a broaching tool having a single row of cutting teeth, as described in connection with the first embodiment, may be used to out a plurality of straight grooves in a work piece, and having a definite angular spacing between the several grooves. In eiecting this, it will be understood that a first groove is cut from an initial or starting position which corresponds to one of the rotative positions of puller sleeve |12 with respect to the driving head |20. Upon completion of the rst groove within the work piece, driving gear |34 is moved out of mesh with driven gear |10 by action of clutch bar |60, as above de' scribed, and puller sleeve |12 and driven gear |10 are then rotated to a position in which detent |18 is in registry with another of the recesses |86 in gear |10. Thereafter, gear |34 may again be moved into mesh with gear |10 and the cutting of the second groove effected in the same manner as the rst groove. Succeeding grooves may be located and cut in a corresponding manner. It will be understood that the number of adjustable positions provided by the recesses 86 should be an even divisor of the number of teeth on gear |10.

Although specific embodiments of the present invention have been shown and described, it will be evident that various changes in the form, number and arrangement of parts may be made in the spirit and scope thereof as defined in the appended claims.

What is claimed is:

l. A machine for operating a broaching tool comprising, in combination, a rectilinearly movable pull bar; a tool head for connecting said pull bar to said broaching tool so that said movement of said pull bar causes rectilinear movement of said broaching tool, said tool head cornf' prising a driven element secured to said broaching tool and a driving element for actuating said driven element; means comprising a spirally cut lead screw for rotating said driving element in timed relation to movement of said pull bar whereby to correspondingly rotate said broaching tool during the rectilinear movement of said broaching too-l; and means for stationarily supporting said lead screw against rotation in any of a plurality of rotative positions.

2. A machine for operating a broaching tool comprising, in combination, a rectilinearly movable pull bar; a tool head for connecting said pull bar member to said broaching tool so that said movement of said pull bar causes rectilinear movement of said bro-aching tool, said tool head comprising a housing, a driven element secured to said broaching tool rotatably journaled in said housing, and a driving element rotatively and slidably journaled in said housing; a member actuable to slide said driving element within said housing into and out of driving relation to said driven element; and means for rotating said driving element in timed relation to movement of said pull bar so as to correspondingly rotate said broaching tool during the rectilinear movement of said broaching tool.

3. A machine for operating a broaching tool comprising, in combination, a rectilinearly movable pull bar; a tool head for connecting said pull bar to said broaching tool so that said movement of said pull bar causes correspondingly rectilinear movement of said broaching tool comprising a housing, a rst gear journaled in the housing and secured to the broach, a second gear journaled in the housing and mated with the rst gear, and a lead screw stationarily supported by said machine in laterally offset relation to the path of travel of the broach and disposed to engage and rotate the second gear during the rectilinear movement oi the pull bar so as to cause said broaching tool to rotate during its rectilinear movement. Y

4. A machine for operating a broaching tool comprising, in combination, a rectilinearly movable pull bar; a tool head for connecting said pull bar to said broaching tool so that said movement of said pull bar causes correspondingly rectilinear movement of said broaching tool comprising a housing, a first gear journaled in the housing and secured to the broach, a second gear .iournaled in the housing and mated with the first gear, a lead screw stationarily supported by said machine in laterally oiIset relation to the path of travel of the broach and disposed to engage and rotate the second gear during the rectilinear movement of the pull bar so as to cause said broaching tool to rotate during its rectilinear movement, and means to adjust the position of the lead screw to adjust the rotative position of the iirst gear and broach corresponding to a particular point in the rectilinear path of the broach.

5. A machine for operating a broaching tool comprising, in combination, a rectilineariy movable pull bar; a tool head for connecting said pull bar to said broaching tool so that said movement of said pull bar causes correspondingly rectilinear movement of said broaching tool comprising a housing, a iirst gear journaled in the housing and secured to the broach, a second gear journaled in the housing and mated with the iirst gear, a lead screw stationarily supported by said machine in laterally offset relation to the path of travel of the broach and disposed to env gage and rotate the second gear during the rectilinear movement of the pull bar so as to cause said broaching tool to rotate during its rectilinear movement, and means to slide one of the gears out of mating relation to the other of the gears to interrupt the rotative drive for the broach.

6. A machine for operating a broaching tool comprising, in combination, a rectilinearly movable pull bar; a tool head for connecting said pull bar to said broaching tool so that said movement of said pull bar causes correspondingly rectilinear movement of said broaching tool comprising a housing, a rst gear Journaied in the housing and secured to the broach, a second gear journaled in the housing and mated with the first gear. a lead screw stationarily supported by said machine in laterally onset relation to the path of travel of the broach and disposed to engage and rotate the second gear during the rectilinear movement of the pull bar so as to cause said broaching tool to rotate during its rectilinear movement, means to slide one of the gears out of mating relation to the otherof the gears to interrupt the rotative drive for the broach, and selectively releasable means for locking the nrst gear .in a predetermined rotative position.

WILLIAM A. HART. 

